As nouns the difference between tav and tas

is that tav is alternative form of lang=en while tas is an alternative spelling of lang=en.

As an acronym TAS is

tool-assisted speedrun.

As an abbreviation TAS is

abbreviation of lang=en|Tasmania.

As an adjective TAS is

used to describe any tool-assisted project.

As a verb TAS is

to make, create, or contribute to a tool-assisted speedrun.